The Why of Ply

I get a little giddy over ply, the twisting together of two or more strands of yarn. I talk about it a lot when I teach spinning, and have even converted a knitter or two to spinning based solely on the power of ply.

Ply does deep-down delectable things to your knitting. It can transform color (hello, marl), texture, durability, weight, and—cue the choir—stitch definition. You can change how your knitting looks just by changing the number of plies in your yarn.

As a knitter choosing a yarn to use for a project, my big three are durability, weight and stitch definition.

Plied yarns are more durable, less susceptible to pilling.Imagine a single-ply yarn, she’s lithe and beautiful, but lonely. When knit into fabric she stands alone against the stretching and rubbing of the world. Imagine she had a sister or two by her side. By twisting strands together, each strand has a lot less of its surface exposed, and they are able to stand strong against the patriarchy of pilling.

Plying can contribute to the weight of a garment. Want a light sweater? Don’t look at a five-ply yarn. There is an exception to this (isn’t there always?): a multi-plied yarn is lighter than a single-ply yarn of the same size. Why? There is air between those plies, and the single-ply is just one solid chunk of fiber.

The sweetest spot of plied yarns is in stitch definition. Depending on the number of plies in your yarn the finished knitted fabric will look, sometimes dramatically, different.

The Yarns

The yarns I’m using are all fine yarns, spun from Merino and Cormo. All three have an intrinsic look of softness and a matte surface.

The Big Three: Single-Ply, 2-Ply, and 3-Ply

Today’s yarns are single-ply (spinners call these singles),2-ply and 3-ply yarns.There are lots of other yarn constructions, yarns that are wrapped, cabled or chained. Those are for another day. Today we’re hitting the big three.

Yarn is built from energy, which we talk about as twist. Single-ply yarn has a single twist in one direction and plied yarns have two twists, one to create the single (in one direction) and one to create the ply (in the opposite direction). These twists create shape and motion in the yarn and contribute to the look and performance of knitted fabric.

Single-ply yarn has a roundish shape that can flatten easily. It has motion in only one direction, which can cause biasing when knit, if there is too much twist in the yarn.

Two-ply yarn is oval in shape. The ply twist moves the strands outward, they push away from each other when knit.

Three-ply yarn is round in shape. The ply twist moves the strands inward, they push toward each other when knit.

Ply, as Applied: Stockinette

Single-ply (left): Single-ply yarn is smooth and stays where you put it when blocked; the stitches line up nicely. In stockinette stitch, it shows every weirdness in your knitting. I row out, my knit and purl tension is very different, and it really shows in stockinette with a single-ply yarn. This is the stitch that will bias if there is any over-twist in the yarn. Sometimes you can block it out, sometimes you can’t.

Two-ply (center): Two-ply yarn has itsown party, look how textured the surface of the 2-ply swatch is. There is no bias with a 2-ply yarn because the plies balance the twist. But because of the outward motion of the two plies pushing away from each other, there is a lot of visual movement on the surface of the knitted fabric. It looks toothy and organic.

Three-ply: Three-ply yarn is round and creates even fabric. The stitches line up and the surface of the knitting is smooth and placid. I am fascinated by the difference in the look of 2-ply and 3-ply yarn in stockinette. The 2-ply is rocking the soul train to funky town, and the 3-ply is ballroom dancing a serene waltz.

Lace

Single-ply: Single-ply yarns are obedient. When you block them into lace, they stay. Because single-ply yarn sometimes flattens and it doesn’t have the extra shadows between plies, the lace has a much softer, less crisp look.

Two-ply: Theobstinate attitude that makes a 2-ply yarn so frisky in stockinette makes it a glorious yarn for lace. The stitches roll away from each other; opening the lace holes. The surface playfulness leads your eye all over the lace pattern.

Three-ply: The roundness of a 3-ply makes smooth lace. The inward twist energy of a 3-ply yarn makes the stitches roll toward each other, causing the lace holes to try to close. What strikes me even more is that 3-ply yarn makes textured stitches stand out in bold. When I look at a lace pattern knit in a 3-ply yarn, the first thing I see are the decreases gorgeously stacked up, overpowering the lace.

Cables

Single-ply: Cables knit out of a single-ply yarn are soft and flat-ish. A good look for a light summer top, but not what I want for an Aran sweater.

Two-ply: A 2-ply cable is a big step up from a single-ply cable. There are edges to these cables, but they really don’t stand up.

Three-ply: A 3-ply (or more) yarn makes the best cables and textured stitches. They roll in and push up. Three-ply yarns make themselves heard. They are crisp, have sharp edges and stand up like the Cliffs of Moher.

Colorwork

Colorwork swatch background colors: French Chambray in Mrs. Crosby single-ply, and St. Barts in Sincere Sheep 2-ply and 3-ply.

Single-ply: Single ply yarns are soft and flow-y when used for any kind of color work. The lines between stitches are undefined because the yarns spread out. This contributes to the classic look of Lopi sweaters, in which colors seem to flow into each other.

Two-ply: The pushing away motion of a 2-ply yarn leads to soft blurry edges between colors. Two-ply yarn is fantastic when you want that misty-water-color-memory look for Fair Isle or Bohus knitting.

Three-ply: Three-ply colorwork knitting has crispy clean edges. Each stitch is distinct, making colors very clear. Three-ply is great for intarsia, or if you want your Scandinavian snowflakes to really stand out.

Ply is so alluring. It’s exciting that an attribute that is so easily overlooked can have such impact on knitted fabric.

Fascinating article and so clearly written. The author distinguishes so effectively — and memorably- all the qualities of each element and how they work together to create a final effect. Thank you so much. So helpful.

This is a great article!! As a sometimes spinner and a retired LYS sales associate, as well as a knitter for many decades, I think that ply and twist are one of the least understood and most important things to know about the yarn we all spend our fortunes on. I would love to see more articles like this.

Nope! Some yarns are labeled as “3 ply” or “4 ply” but this is very old school (I’m thinking of Rowan and Jamiesons). The yarns of today typically say nothing on the label about their construction. We must stay close to Jillian, and examine yarns ourselves to figure it out.

When you do see “2-ply” (or 3 or 4) on UK, Australian, or NZ yarns, be careful! There is an older system of yarn weight that also uses these terms with little to no relationship to yarn construction!

I don’t think there’s anything wrong with untwisting an inch of yarn at the end of a ball or skein to examine the plies, but it’s polite to get permission first. If your trusty LYS staff can’t tell you the structure of the yarn they’re selling, and it’s not on the Ravelry page or the manufacturer’s website, ask if you can figure it out for yourself. It’s an entirely reasonable thing to want to know before buying a yarn.

What a wonderful explanation of ply and how it affects the finished piece. I like the squishy feel of single-ply yarns, but man, are they difficult to work with sometimes. It’s difficult to find a yarn manufacturer that gets the twist just right in a single-ply.

This is a terrific review of last night’s meeting of our new knitting guild here in Puddetown (AKA Portland, OR): https://www.puddletownknittersguild.com/guild-meetings.html Chelsea, our speaker, also talked about the ends of the strands spun into yarn; in singles, the ends tend to poke out because there’s no next-door strand twisted around them to keep them in, thus single-ply yarn tends to pill.

Jillian! thank you! great informative article (hard to do with the written word) and clearly laid out. I have been knitting for decades under the English system of 2 – 3 – 4 ply wool, and knew that related to weight rather than construction. This really clarifies the importance of choosing the correct yarn, not just colour and weight!

Wow! Thank you so much for dropping this knowledge. I thought I knew the (very) basics, but didn’t think through to the implications when knitting. So glad I subscribe – I learned many useful things today!

Very interesting & informative article. Was disappointed in examples in some of the photos: each of the 2-color samples used different colors thus making it difficult to tell if the “definition” was d/t the ply or the brighter color.

This is the kind of visual learning that I need to understand the delicacies and differences of plies. Thank you so very much! I am an avid yarn-substituter and this adds so much more information than I had before.

This is incredible. I honestly have never had anyone discuss ply with me before. now looking back on several projects, color work and lace, I understand why it is important to either stick with the yarn the designer suggested or make sure that the ply matches and not just the weight of the yarn. Wow. My mind is absolutely blown.

Thank you! I am fascinated by the effects of ply and I want to try out your experiments with crocheted garments. I wonder if the twists of double and treble crochet stitches will show the texture and bias too. I’ll definitely share your article on my page. Crocheters are hungry for more yarn education, with more and more garment patterns being featured.

Love the article, but I hear my fibre arts professor growling at a student who called “singles” a type of “ply.”
Plyed is the opposite of single.
Or, as my professor put it, “Once upon a time you were a virgin. Now you’re not. You can’t be both!”

The more I spin, the more sense this makes; and the more I knit, the more sense it makes. Can you say, big fat Aran single to make Kate’s Carbeth pullover? Yes! But the big fat Aran plied for the Carbeth cardigan, that needs more structure.
And, misty-water-color-memory? Hahaha…had me humming “The Way We Were” all day!